Neutrinos and antineutrinos are presently generated by radioactive beta decay, man-made nuclear reactors and nuclear processes in the sun and other stars. Generation of neutrinos and antineutrinos from any of these sources has certain disadvantages. Neutrino and antineutrino emission from heavenly bodies is basically random and unpredictable. Hence, amplitude modulation of neutrinos emitted from heavenly bodies is not feasible. While neutrino and antineutrino emission from radioactive beta decay sources and man-made nuclear reactors is relatively predictable and can therefore be reliably amplitude modulated, such sources pose certain problems with regard to health of personnel located in proximity thereto, and are relatively expensive. Of course, it is desirable to provide neutrino sources having predictable, relatively constant amplitude, so that such sources can be amplitude modulated for communication purposes. These problems of prior art neutrino antineutrino sources could be overcome if electrical energy could be employed to power a neutrino source.
Neutrino and antineutrino communication is highly desirable because of the capability of neutrinos and antineutrinos to penetrate the earth and propagate between diametrically opposed points on the surface of the earth. In addition, the frequency of neutrino and antineutrino propagation, approximately 3.times.10.sup.20 Hz, enables many messages to be modulated on neutrino and antineutrino emissions.
Neutrino and antineutrino emissions are generally isotropic. For communication applications, it is desirable for a beam of neutrinos to be derived from an anisotropic neutrino antineutrino source.
It is, accordingly, an object of the present invention to provide a new and improved apparatus for and method of generating neutrinos and/or antineutrinos; in the claims of this document, the generic term "neutrino type particles" is used to designate neutrinos and/or antineutrinos.
Another object of the invention is to provide a new and improved neutrino antineutrino source wherein electric power is used as an excitation source, rather than nuclear reactor or beta decay sources.
Another object of the present invention is to provide a new and improved method of and apparatus for generating neutrinos and/or antineutrinos, which method and apparatus is particularly suited for deriving neutrino emissions that can be modulated.
A further object of the present invention is to provide a new and improved apparatus for generating a neutrino beam.
An additional object of the present invention is to provide a new and improved neutrino antineutrino source that derives a predictable, relatively constant level of neutrinos and antineutrinos.
In my earlier U.S. Pat. Nos. 4,576,777 and 4,732,728, respectively issued Mar. 18, 1986 and Mar. 22, 1988, there are disclosed methods and structures for detecting neutrino antineutrino energy. In the '777 patent coherent inelastic neutrino antineutrino scatterers are employed, while in the '728 patent elastic neutrino antineutrino scatterers are used. In the '777 patent, individual atoms in a stiff crystal absorb energy from the neutrino and/or antineutrino particles to scatter the particles and produce stimulated coherent radiant energy fields. The coherent fields produced by the individual atoms are detected to provide an indication of the presence of the neutrino or antineutrino particles in the beam.
The crystals employed in my prior art patents are relatively large and nearly perfect, having great stiffness, i.e., high Debye temperatures. Momentum of incident neutrinos or antineutrinos is exchanged by quarks in nuclei of atoms forming the crystal when energy is exchanged with a nuclear spin system in a magnetic field. The entire crystal recoils as a single entity. Detection is accomplished by observing changes in nuclear spin system temperature.
In the processes and apparatus of my aforementioned prior patents, one or a very small number of nuclei in the very stiff crystal scatters neutrinos or antineutrinos by momentum exchange, by one or a very small number of nuclei. Momentum exchange at a nucleus is quickly transferred to the crystal center of mass. Usually, the entire crystal recoils as a single entity, without exciting sound vibrations in the crystal. The scattering site cannot be determined by subsequent measurements, an important feature in obtaining a high probability process.
In my '777 patent, nuclear magnetic resonance techniques are employed for neutrino and antineutrino detection. A bulk material having nuclei with non-zero spin non-zero magnetic moments is employed. The material has sufficient stiffness to recoil as a single entity after absorbing momentum from each neutrino or antineutrino incident thereon. Exemplary materials are described as crystals of sapphire or silicon, respectively including the isotopes 27Al and 29Si, that exhibit nuclear magnetic resonance properties when excited with appropriate magnetic fields. While the material is irradiated by neutrinos or antineutrinos, a magnetic field applied to it causes the nuclei to normally precess about the magnetic field longitudinal axis at a predetermined angle. The neutrino may cause a shift in the nuclei precessing angle or may modify the quantum states of the nuclei spins by altering correlations established by applied electromagnetic fields. The nuclei changes are detected by using a nuclear magnetic resonance detecting apparatus. The magnetic field intensity necessary to detect the nuclear magnetic resonance field is quantified in the '777 patent as ##EQU1## where: E.sub..nu. =the energy of neutrinos in the beam;
.mu..sub.m =the scattering nuclear magnetic moment of the material; PA1 .beta..sup.2 =the fraction of nuclei of the material with moments parallel to the direction of the magnetic field; and PA1 N=the total number of neutrino scatterers of the material.
A crystal is considered to be stiff if it has the proper recoil properties as represented by a crystal Debye temperature exceeding 500.degree. Kelvin. This definition of a stiff crystal is employed in the present specification and claims.
In accordance with one feature of the '728 patent, neutrino and/or antineutrino particles in a beam incident on scatterers of a crystal mounted on a mechanical resonator are amplitude modulated at the resonant frequency of the mechanical resonator or a harmonic thereof. The amplitude modulation is provided by chopping the neutrino or antineutrino beam incident on the crystal containing elastic coherent scatterers mounted on the mechanical resonator. The neutrino beam is preferably chopped by mounting a plurality of scatterers for the neutrino and/or antineutrino particles in the beam on a structure turned by a motor. Such a modulation mechanism, however, does not provide amplitude modulation in response to variable amplitude signals. Hence in my prior art modulator amplitude variations of a modulation source does not result in a concomitant variation of neutrino antineutrino emissions.
Accordingly, a further object of the present invention is to provide a new and improved neutrino antineutrino amplitude modulator.
An additional object of the invention is to provide a new and improved method of and apparatus for amplitude modulating neutrinos and/or antineutrinos in response to a variable amplitude signal so that as variations in the amplitude of the signal occur there are concomitant variations in the amplitude of the neutrinos and/or antineutrinos derived from the modulator or by the modulation process.
An additional object of the present invention is to provide a new and improved method of and apparatus for amplitude modulating neutrinos and/or antineutrinos, wherein the transparency of a scatterer to neutrinos is controlled for the neutrinos and/or antineutrinos in response to the amplitude of a modulating signal.